Massey Ferguson 19 – AIRCON: Issue With The Heater Valve (AIRCON)

A malfunction in the cab's climate control system where the heater control valve is either blocked open, failing to actuate, or experiencing a signal/voltage issue preventing it from regulating the flow of hot engine coolant into the cab heater core.

• 7724S
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 7720S
• 7716
• 7718
• 7726
• 7715
• 7616
• 7618
• 7619
• 7626
• 7726S
• 7624
• 7614
• 7718S
• 7620
• 7719
• 7714
• 7716S
• 7622
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 5710SL
• 5711SL
• 5712SL
• 5713SL

1. 1

   Check Hose Routing: Verify that the heater hoses have not been installed in reverse order during previous maintenance. Reversed hoses expose the valve outlet to high pressure, which can damage the valve and force it open.

2. 2

   Actuation Check: For cable-operated valves, check the cable adjustment to ensure the valve is fully closing. For electronic pneumatic/solenoid valves, check the wiring harness for continuity between the AIRCON module and the valve.

3. 3

   Module Voltage: Verify that the Air Conditioning Module is receiving proper voltage, as voltage drops can trigger false valve faults.

4. 4

   Physical Inspection: Check if the valve is physically seized or blocked open by debris in the coolant system.

1. 1

   Access the HVAC Unit

   The heater valve is typically located near the air conditioner unit. Depending on the exact tractor model, this usually requires removing the top cab roof plate or accessing the side of the HVAC unit inside the cab headliner.

2. 2

   Pinch Off Coolant Lines

   Clamp the heater hoses leading to and from the engine to prevent excessive coolant loss.

3. 3

   Disconnect the Valve

   Remove the hose clamps and pull the heater hoses off the valve. Note the exact orientation of the inlet and outlet hoses to prevent reversing them upon reinstallation. Disconnect the electrical connector (or the control cable, depending on the specific valve type).

4. 4

   Remove and Replace

   Unbolt the faulty heater valve from its mounting bracket and install the new OEM replacement.

5. 5

   Reassembly

   Reconnect the hoses in the correct flow direction. Reconnect the electrical harness or control cable.

6. 6

   System Bleed and Test

   Remove the hose clamps, start the tractor, and let it reach operating temperature. Turn the cab heater on full blast to bleed any trapped air from the heater core. Check for leaks and verify that the AIRCON module clears the fault code.